GLBP: does it only work in a /24 subnet?

Hey guys,

So I'm putting proof of concept of the lab into the configs and I'm finding I'm unable to get the GLBP Virtual IP working in the AREA 0 backbone. I'm using the last subnet range of a /27. The inerfaces coming into the the twin 2821's are on the 172.16.10.0 and 172.16.10.4 subnets respectfully with the vritual being 10.28.

But I'm finding online that most people do Gateway Load Balanicng Protocol on a /24.

Now what I've been doing is adding each of the .252 ranges to vlans on each uplinks between the 3750G's and the 2821's and then the etherchannel between the 3750G's into thier own switchport access vlan groups for the routers and a vlan for the etherchannel.

However I'm wondering if I need to now just run the entire AREA 0 backbones connections on each individual port with a 'no switchport' and literally enter in the areas manually and change the Area 0 from a VLSM of a /27 on each uplink (.252) to just a .224 subnet range so all of the devices in the 172.16.10.0 /27 range can see the Virtual IP address.

I have OSPF AREA 0 set to '172.16.10. 0.0.0.31' so to me in my mind it should matter but manybe I'm not doing this correctly.

Like I'm thinking since I'm using VLSM and making them all use 255.255.255.252 ranges I think that's why it doesnt work, the question is how would I make it work for a 255.255.255.224 range? - my only theory is disabling the switchports so no vlans can be used on the 3750's and setting up the ip address manually to each port and instead of their current IE 172.16.10.9 255.255.255.252 associated to a vlan number they would be say "Gig1/0/1 - ip address 172.16.10.9 255.255.255.224" without a vlan association.

Does this makes sense, if so could someone provide enlightment for me.

Here is the config of one of the 2821's:

load-balancing Load balancing method
name Redundancy name
preempt Overthrow lower priority designated routers
priority Priority level
timers Adjust GLBP timers
weighting Gateway weighting and tracking

2821-VRRP-1(config-if)#^Z
2821-VRRP-1#wr
Building configuration...

[OK]
2821-VRRP-1#
*Oct 4 00:41:45.523: %SYS-5-CONFIG_I: Configured from console by console
2821-VRRP-1#clear ip osp
2821-VRRP-1#clear ip ospf pro
2821-VRRP-1#clear ip ospf process
Reset ALL OSPF processes? [no]: y
2821-VRRP-1#
*Oct 4 00:42:18.459: %OSPF-5-ADJCHG: Process 1, Nbr 4.4.4.4 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Oct 4 00:42:18.483: %OSPF-5-ADJCHG: Process 1, Nbr 4.4.4.4 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
2821-VRRP-1#od

OSPF Router with ID (1.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 8 0x80000005 0x005C32 1
2.2.2.2 2.2.2.2 11 0x80000005 0x00AFDE 1
3.3.3.3 3.3.3.3 15 0x8000000C 0x00CDFF 2
4.4.4.4 4.4.4.4 1675 0x8000000A 0x00546A 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
172.16.10.2 3.3.3.3 15 0x80000004 0x00EF61
172.16.10.6 4.4.4.4 1891 0x80000001 0x009FAC
172.16.10.10 4.4.4.4 1675 0x80000007 0x00CF6A
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#ru
Building configuration...

Current configuration : 1600 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname 2821-VRRP-1
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
!
dot11 syslog
ip source-route
!
!
ip cef
!
!
no ip domain lookup
no ipv6 cef
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
voice-card 0
!
!
!
!
!
username trevor privilege 15 password 7 00071A150754
archive
log config
hidekeys
!
!
!
!
!
!
interface GigabitEthernet0/0
ip address 172.16.10.5 255.255.255.252
duplex auto
speed auto
glbp 1 ip 172.16.10.29
glbp 1 name GLBP-for-CORE-OSPF-AREA-O
!
interface GigabitEthernet0/1
ip address 192.168.115.32 255.255.255.192
duplex auto
speed auto
!
interface Serial0/0/0
no ip address
shutdown
!
interface Serial0/1/0
no ip address
shutdown
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 172.16.10.0 0.0.0.31 area 0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
banner login ^C Username: trevor | Password: cisco | Enable: cisco ^C
alias exec i show ip inter br
alias exec p show protocols
alias exec o show ip ospf
alias exec od show ip ospf database
alias exec cd show cdp neighbors
alias exec st show spanning-tree
alias exec ru show running-config
!
line con 0
exec-timeout 0 0
logging synchronous
login local
line aux 0
line vty 0 4
exec-timeout 0 0
logging synchronous
login local
line vty 5 15
exec-timeout 0 0
logging synchronous
login local
!
scheduler allocate 20000 1000
end

2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#od

OSPF Router with ID (1.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 1078 0x80000005 0x005C32 1
2.2.2.2 2.2.2.2 1081 0x80000005 0x00AFDE 1
3.3.3.3 3.3.3.3 1086 0x8000000C 0x00CDFF 2
4.4.4.4 4.4.4.4 732 0x8000000B 0x00526B 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
172.16.10.2 3.3.3.3 1086 0x80000004 0x00EF61
172.16.10.6 4.4.4.4 988 0x80000002 0x009DAD
172.16.10.10 4.4.4.4 732 0x80000008 0x00CD6B
2821-VRRP-1#cd
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID
3750G-CORE-2 Gig 0/0 176 R S I WS-C3750G Gig 1/0/1
2821-VRRP-1#p
Global values:
Internet Protocol routing is enabled

2821-VRRP-1#i
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#ru
Building configuration...

Current configuration : 1600 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname 2821-VRRP-1
!
boot-start-marker
boot-end-marker
!
logging message-counter syslog
!
no aaa new-model
!
dot11 syslog
ip source-route
!
!
ip cef
!
!
no ip domain lookup
no ipv6 cef
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
voice-card 0
!
!
!
!
!
username trevor privilege 15 password 7 00071A150754
archive
log config
hidekeys
!
!
!
!
!
!
interface GigabitEthernet0/0
ip address 172.16.10.5 255.255.255.252
duplex auto
speed auto
glbp 1 ip 172.16.10.29
glbp 1 name GLBP-for-CORE-OSPF-AREA-O
!
interface GigabitEthernet0/1
ip address 192.168.115.32 255.255.255.192
duplex auto
speed auto
!
interface Serial0/0/0
no ip address
shutdown
!
interface Serial0/1/0
no ip address
shutdown
!
router ospf 1
router-id 1.1.1.1
log-adjacency-changes
network 172.16.10.0 0.0.0.31 area 0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
!
!
!
control-plane
!
!
!
!
!
!
!
!
banner login ^C Username: trevor | Password: cisco | Enable: cisco ^C
alias exec i show ip inter br
alias exec p show protocols
alias exec o show ip ospf
alias exec od show ip ospf database
alias exec cd show cdp neighbors
alias exec st show spanning-tree
alias exec ru show running-config
!
line con 0
exec-timeout 0 0
logging synchronous
login local
line aux 0
line vty 0 4
exec-timeout 0 0
logging synchronous
login local
line vty 5 15
exec-timeout 0 0
logging synchronous
login local
!
scheduler allocate 20000 1000
end

2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#od

OSPF Router with ID (1.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 1078 0x80000005 0x005C32 1
2.2.2.2 2.2.2.2 1081 0x80000005 0x00AFDE 1
3.3.3.3 3.3.3.3 1086 0x8000000C 0x00CDFF 2
4.4.4.4 4.4.4.4 732 0x8000000B 0x00526B 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
172.16.10.2 3.3.3.3 1086 0x80000004 0x00EF61
172.16.10.6 4.4.4.4 988 0x80000002 0x009DAD
172.16.10.10 4.4.4.4 732 0x80000008 0x00CD6B
2821-VRRP-1#cd
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID
3750G-CORE-2 Gig 0/0 176 R S I WS-C3750G Gig 1/0/1
2821-VRRP-1#p
Global values:
Internet Protocol routing is enabled

2821-VRRP-1#i
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 172.16.10.5 YES manual up up
GigabitEthernet0/1 192.168.115.32 YES manual up up
Serial0/0/0 unassigned YES NVRAM administratively down down
Serial0/1/0 unassigned YES NVRAM administratively down down
2821-VRRP-1#ping 172.16.10.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
2821-VRRP-1#ping 172.16.10.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
2821-VRRP-1#ping 172.16.10.29

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.29, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
2821-VRRP-1#ping 172.16.10.9

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.9, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
2821-VRRP-1#ping 172.16.10.10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.10, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
2821-VRRP-1#ping 172.16.10.5

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
2821-VRRP-1#ping 172.16.10.6

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.10.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
2821-VRRP-1#

Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 172.16.10.5 YES manual up up
GigabitEthernet0/1 192.168.115.32 YES manual up up
Serial0/0/0 unassigned YES NVRAM administratively down down
Serial0/1/0 unassigned YES NVRAM administratively down down
2821-VRRP-1#

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Comments

verbhertz

GLBP works independent of your OSPF area and needs the same broadcast domain to communicate. I'll go over your configs when I get more time tonight and try to be more helpful.

Edit: can you post a topology drawing of what you are trying to accomplish? That will be helpful.

Edit2: your virtual IP is not in the same subnet as your Gig0/0 network.

Edit3: can you post a show glbp summary from all devices also. From your post I don't see any real question, what do you think is broken?

Deathmage

w00t fixed it, I got up and got some coffee and started thinking, now it's working. I just made the core 2821's on a seperate vlan but instead added the vlan to the OSPF AREA 0. Both of the 2821's that touch the 3750G's at the core are on one vlan but instead of them being in a VLSM'd .252 on a per uplink basis I just changed it to a .240 range and allowed for the 172.16.15.1 address range to be kept open and whalla...victory!!!!!!!

so on that note at 11:40 at night the home lab's Core layer is now finished, moving on the the distro layer.

Here is a config of what I did......

A summary of U.S. laws governing Cisco cryptographic products may be found at:
Export Compliance Product Report Application

If you require further assistance please contact us by sending email to
export@cisco.com.

Cisco 2821 (revision 49.46) with 251904K/10240K bytes of memory.
Processor board ID FTX1026A4ST
2 Gigabit Ethernet interfaces
2 Serial interfaces
1 Serial(sync/async) interface
DRAM configuration is 64 bits wide with parity enabled.
239K bytes of non-volatile configuration memory.
125440K bytes of ATA CompactFlash (Read/Write)

SETUP: new interface Serial0/2/0 placed in "shutdown" state

Press RETURN to get started!

*Oct 4 02:30:48.827: SERVICE_MODULE(Serial0/0/0): self test finished: Passed
*Oct 4 02:30:51.623: SERVICE_MODULE(Serial0/1/0): self test finished: Passed
*Oct 4 02:30:57.119: %LINEPROTO-5-UPDOWN: Line protocol on Interface VoIP-Null0, changed state to up
*Oct 4 02:30:57.123: %LINK-3-UPDOWN: Interface GigabitEthernet0/0, changed state to up
*Oct 4 02:30:57.123: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
*Oct 4 02:30:57.123: %LINK-3-UPDOWN: Interface Serial0/0/0, changed state to down
*Oct 4 02:30:57.123: %LINK-3-UPDOWN: Interface Serial0/1/0, changed state to down
*Oct 4 02:30:57.123: %LINK-3-UPDOWN: Interface Serial0/2/0, changed state to down
*Oct 4 02:30:58.547: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up
*Oct 4 02:30:58.547: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
*Oct 4 02:30:58.547: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/0/0, changed state to down
*Oct 4 02:30:58.547: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1/0, changed state to down
*Oct 4 02:30:58.547: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/2/0, changed state to down
*Oct 4 02:30:58.967: %SYS-5-CONFIG_I: Configured from memory by console
*Oct 4 02:31:00.815: %LINK-5-CHANGED: Interface Serial0/0/0, changed state to administratively down
*Oct 4 02:31:00.835: %LINK-5-CHANGED: Interface Serial0/1/0, changed state to administratively down
*Oct 4 02:31:00.971: %LINK-5-CHANGED: Interface Serial0/2/0, changed state to administratively down
*Oct 4 02:31:02.739: %SYS-5-RESTART: System restarted --
Cisco IOS Software, 2800 Software (C2800NM-SPSERVICESK9-M), Version 12.4(24)T4, RELEASE SOFTWARE (fc2)
Technical Support: Support and Documentation - Cisco Systems
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Fri 03-Sep-10 05:39 by prod_rel_team
*Oct 4 02:31:02.743: %SNMP-5-COLDSTART: SNMP agent on host 2821-VRRP-1 is undergoing a cold start
*Oct 4 02:31:26.811: %OSPF-5-ADJCHG: Process 1, Nbr 4.4.4.4 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
*Oct 4 02:32:58.763: %OSPF-5-ADJCHG: Process 1, Nbr 4.4.4.4 on GigabitEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired Username: trevor | Password: cisco | Enable: cisco

User Access Verification

Username: trevor
Password:
2821-VRRP-1#config t
Enter configuration commands, one per line. End with CNTL/Z.
2821-VRRP-1(config)#inter gig0/0
2821-VRRP-1(config-if)#no ip add
2821-VRRP-1(config-if)#ip add 172.16.15.9 255.255.255.240
2821-VRRP-1(config-if)#exit
2821-VRRP-1(config)#router ospf
% Incomplete command.

2821-VRRP-1(config)#router ospf 1
2821-VRRP-1(config-router)#network 172.16.15.0 0.0.0.31 area 0
2821-VRRP-1(config-router)#
*Oct 4 02:38:20.775: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
2821-VRRP-1(config-router)#
*Oct 4 02:41:04.539: %OSPF-5-ADJCHG: Process 1, Nbr 3.3.3.3 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
2821-VRRP-1(config-router)#
*Oct 4 02:42:39.055: %OSPF-5-ADJCHG: Process 1, Nbr 4.4.4.4 on GigabitEthernet0/0 from LOADING to FULL, Loading Done
2821-VRRP-1(config-router)#ex
*Oct 4 02:44:37.939: %GLBP-4-DIFFVIP1: GigabitEthernet0/0 Grp 1 active routers virtual
IP address 172.16.15.1 is different to the locally configured
address 172.16.10.29
2821-VRRP-1(config-router)#exit
2821-VRRP-1(config)#
2821-VRRP-1(config)#show runn
2821-VRRP-1(config)#^Z
2821-VRRP-1#show
*Oct 4 02:45:00.791: %SYS-5-CONFIG_I: Configured from console by trevor on console
2821-VRRP-1#show run
2821-VRRP-1#show running-config
*Oct 4 02:45:08.759: %GLBP-4-DIFFVIP1: GigabitEthernet0/0 Grp 1 active routers virtual
IP address 172.16.15.1 is different to the locally configured
address 172.16.10.29
2821-VRRP-1#show running-config gi0/0
^
% Invalid input detected at '^' marker.

2821-VRRP-1#show running-config gig0/0
^
% Invalid input detected at '^' marker.

2821-VRRP-1#show running-config interface gig0/0
Building configuration...

Current configuration : 144 bytes
!
interface GigabitEthernet0/0
ip address 172.16.15.9 255.255.255.240
duplex auto
speed auto
glbp 1 ip 172.16.10.29
glbp 1 name GLBP1
end

2821-VRRP-1#
2821-VRRP-1#config t
Enter configuration commands, one per line. End with CNTL/Z.
2821-VRRP-1(config)#
*Oct 4 02:45:41.451: %GLBP-4-DIFFVIP1: GigabitEthernet0/0 Grp 1 active routers virtual
IP address 172.16.15.1 is different to the locally configured
address 172.16.10.29
2821-VRRP-1(config)#glbp 1 ip 172.16.15.1
^
% Invalid input detected at '^' marker.

2821-VRRP-1(config)#glbp 1 ip 172.16.15.1
*Oct 4 02:46:12.043: %GLBP-4-DIFFVIP1: GigabitEthernet0/0 Grp 1 active routers virtual
IP address 172.16.15.1 is different to the locally configured
address 172.16.10.29
2821-VRRP-1(config)#inter gig0/0
2821-VRRP-1(config-if)#glbp 1 ip 172.16.15.1
2821-VRRP-1(config-if)#
2821-VRRP-1(config-if)#
2821-VRRP-1(config-if)#^Z
2821-VRRP-1#w
*Oct 4 02:46:45.475: %SYS-5-CONFIG_I: Configured from console by trevor on console
2821-VRRP-1#wr
Building configuration...

[OK]
2821-VRRP-1#
*Oct 4 02:46:48.379: %GLBP-6-FWDSTATECHANGE: GigabitEthernet0/0 Grp 1 Fwd 2 state Listen -> Active
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#show glbp
GigabitEthernet0/0 - Group 1
State is Standby
1 state change, last state change 00:00:03
Virtual IP address is 172.16.15.1
Hello time 3 sec, hold time 10 sec
Next hello sent in 1.792 secs
Redirect time 600 sec, forwarder timeout 14400 sec
Preemption disabled
Active is 172.16.15.5, priority 110 (expires in 10.304 sec)
Standby is local
Priority 100 (default)
Weighting 100 (default 100), thresholds: lower 1, upper 100
Load balancing: round-robin
IP redundancy name is "GLBP1"
Group members:
0018.737a.0d08 (172.16.15.9) local
001f.ca87.2960 (172.16.15.5)
There are 2 forwarders (1 active)
Forwarder 1
State is Listen
MAC address is 0007.b400.0101 (learnt)
Owner ID is 001f.ca87.2960
Time to live: 14398.528 sec (maximum 14400 sec)
Preemption enabled, min delay 30 sec
Active is 172.16.15.5 (primary), weighting 100 (expires in 9.024 sec)
Forwarder 2
State is Active
1 state change, last state change 00:00:15
MAC address is 0007.b400.0102 (default)
Owner ID is 0018.737a.0d08
Preemption enabled, min delay 30 sec
Active is local, weighting 100
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#show glbp brief
Interface Grp Fwd Pri State Address Active router Standby router
Gi0/0 1 - 100 Standby 172.16.15.1 172.16.15.5 local
Gi0/0 1 1 - Listen 0007.b400.0101 172.16.15.5 -
Gi0/0 1 2 - Active 0007.b400.0102 local -
2821-VRRP-1#
2821-VRRP-1#p
Global values:
Internet Protocol routing is enabled

2821-VRRP-1#i
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 172.16.15.9 YES manual up up
GigabitEthernet0/1 192.168.115.32 YES NVRAM up up
Serial0/0/0 unassigned YES NVRAM administratively down down
Serial0/1/0 unassigned YES NVRAM administratively down down
Serial0/2/0 unassigned YES unset administratively down down
2821-VRRP-1#
2821-VRRP-1#od

OSPF Router with ID (1.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count
1.1.1.1 1.1.1.1 544 0x8000000A 0x00EE8D 1
2.2.2.2 2.2.2.2 545 0x80000007 0x00700B 1
3.3.3.3 3.3.3.3 375 0x8000000A 0x004B73 2
4.4.4.4 4.4.4.4 287 0x8000000D 0x004B63 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum
172.16.10.10 4.4.4.4 575 0x80000003 0x00D766
172.16.15.5 2.2.2.2 287 0x80000003 0x003EFF
2821-VRRP-1#
2821-VRRP-1#
2821-VRRP-1#show glbp brief
Interface Grp Fwd Pri State Address Active router Standby router
Gi0/0 1 - 100 Standby 172.16.15.1 172.16.15.5 local
Gi0/0 1 1 - Listen 0007.b400.0101 172.16.15.5 -
Gi0/0 1 2 - Active 0007.b400.0102 local -
2821-VRRP-1#ping 172.16.15.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.15.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
2821-VRRP-1#

One of the 3750G Core Switch:

User Access Verification

Username:
Username: trevor
Password:
3750G-CORE-1#show run
3750G-CORE-1#show running-config
Building configuration...

Current configuration : 4602 bytes
!
version 12.2
no service pad
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname 3750G-CORE-1
!
boot-start-marker
boot-end-marker
!
enable secret 5 $1$Y.3a$2QRFUYOl52VzsNo5nwTAY1
!
username trevor privilege 15 password 0 cisco
!
!
no aaa new-model
switch 2 provision ws-c3750g-24t
system mtu routing 1500
authentication mac-move permit
ip subnet-zero
ip routing
!
!
!
!
crypto pki trustpoint TP-self-signed-3402655360
enrollment selfsigned
subject-name cn=IOS-Self-Signed-Certificate-3402655360
revocation-check none
rsakeypair TP-self-signed-3402655360
!
!
crypto pki certificate chain TP-self-signed-3402655360
certificate self-signed 01
30820245 308201AE A0030201 02020101 300D0609 2A864886 F70D0101 04050030
31312F30 2D060355 04031326 494F532D 53656C66 2D536967 6E65642D 43657274
69666963 6174652D 33343032 36353533 3630301E 170D3933 30333031 30303031
32385A17 0D323030 31303130 30303030 305A3031 312F302D 06035504 03132649
4F532D53 656C662D 5369676E 65642D43 65727469 66696361 74652D33 34303236
35353336 3030819F 300D0609 2A864886 F70D0101 01050003 818D0030 81890281
8100E849 27ED7ABE 7088E556 438994ED 910A7CDC AA4C1BAC C4B9DBB1 6E95FBB0
1B2E4123 4AE0C7C6 5282B6D3 867E42F0 FDDE5F51 9BAA5F45 D057C165 AD29081D
0623166C AB5D7722 10CF5C55 CACBF869 F67975EB 826B533A 9CE0D161 063C4ADC
2FA6B4F6 7AB683BE 4C478739 1185FB88 591668EA F6B917A2 474FD0E5 E71C11BF
20E10203 010001A3 6D306B30 0F060355 1D130101 FF040530 030101FF 30180603
551D1104 11300F82 0D333735 30472D43 4F52452D 312E301F 0603551D 23041830
168014D6 D36080CE FFF26189 72C3C4B9 350967CC 76C81630 1D060355 1D0E0416
0414D6D3 6080CEFF F2618972 C3C4B935 0967CC76 C816300D 06092A86 4886F70D
01010405 00038181 007348F8 3B63BB0E D2EBA3B9 FDDCBB02 39432AB0 33AE7582
8484CBEF 9420D784 53494E88 5B3C76D7 BC7C283C 194DBA48 900CF95D 5BEB885E
C6A62CCB B194A865 11AB4EF2 860554C6 6D118393 2C597A22 BB718F83 675137FC
F2F99D0F B472F42D 753B4D23 C88CA278 A68D013C 981B36D3 3B94DB21 46EFF7AC
8F1C0253 42A610CE 85
quit
!
!
!
spanning-tree mode pvst
spanning-tree etherchannel guard misconfig
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
!
!
!
interface Loopback0
ip address 3.3.3.3 255.255.255.255
!
interface Port-channel1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,10,20,30,40,50
switchport mode trunk
!
interface GigabitEthernet2/0/1
switchport access vlan 20
switchport mode access
!
interface GigabitEthernet2/0/2
!
interface GigabitEthernet2/0/3
!
interface GigabitEthernet2/0/4
!
interface GigabitEthernet2/0/5
!
interface GigabitEthernet2/0/6
!
interface GigabitEthernet2/0/7
!
interface GigabitEthernet2/0/8
!
interface GigabitEthernet2/0/9
!
interface GigabitEthernet2/0/10
!
interface GigabitEthernet2/0/11
!
interface GigabitEthernet2/0/12
!
interface GigabitEthernet2/0/13
!
interface GigabitEthernet2/0/14
!
interface GigabitEthernet2/0/15
!
interface GigabitEthernet2/0/16
!
interface GigabitEthernet2/0/17
!
interface GigabitEthernet2/0/18
switchport access vlan 20
!
interface GigabitEthernet2/0/19
switchport access vlan 30
!
interface GigabitEthernet2/0/20
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,10,20,30,40,50
switchport mode trunk
channel-group 1 mode desirable
!
interface GigabitEthernet2/0/21
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,10,20,30,40,50
switchport mode trunk
channel-group 1 mode desirable
!
interface GigabitEthernet2/0/22
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,10,20,30,40,50
switchport mode trunk
channel-group 1 mode desirable
!
interface GigabitEthernet2/0/23
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,10,20,30,40,50
switchport mode trunk
channel-group 1 mode desirable
!
interface GigabitEthernet2/0/24
!
interface Vlan1
no ip address
shutdown
!
interface Vlan20
ip address 172.16.10.2 255.255.255.252
!
interface Vlan30
ip address 172.16.10.9 255.255.255.252
!
router ospf 1
router-id 3.3.3.3
log-adjacency-changes
network 172.16.10.0 0.0.0.31 area 0
!
ip classless

3750G-CORE-1#config t
Enter configuration commands, one per line. End with CNTL/Z.
3750G-CORE-1(config)#inter vlan 20
3750G-CORE-1(config-if)#no ip add
3750G-CORE-1(config-if)#ip add 172.16.15.6 255.255.255.240
3750G-CORE-1(config-if)#exit
3750G-CORE-1(config)#exit
3750G-CORE-1#
3750G-CORE-1#
3750G-CORE-1#sho
*Mar 1 01:10:25.123: %SYS-5-CONFIG_I: Configured from console by trevor on console
3750G-CORE-1#show ru
3750G-CORE-1#show running-config inter gig2/0/1
Building configuration...

Current configuration : 89 bytes
!
interface GigabitEthernet2/0/1
switchport access vlan 20
switchport mode access
end

3750G-CORE-1#
3750G-CORE-1#
3750G-CORE-1#config t
Enter configuration commands, one per line. End with CNTL/Z.
3750G-CORE-1(config)#router ospf 1
3750G-CORE-1(config-router)#network 172.16.15.0 0.0.0.31 area 0
3750G-CORE-1(config-router)#exit
3750G-CORE-1(config)#exit
3750G-CORE-1#
*Mar 1 01:11:07.083: %OSPF-5-ADJCHG: Process 1, Nbr 1.1.1.1 on Vlan20 from LOADING to FULL, Loading Done
3750G-CORE-1#
*Mar 1 01:11:08.190: %SYS-5-CONFIG_I: Configured from console by trevor on console
3750G-CORE-1#
*Mar 1 01:11:11.856: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Vlan20 from LOADING to FULL, Loading Done
3750G-CORE-1#ping 172.16.15.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.15.1, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 1/2/8 ms
3750G-CORE-1#ping 172.16.15.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.16.15.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/8 ms
3750G-CORE-1#